main() {
  //数据类型
  num age1 = 18;

  int age2 = 19;

  double age3 = 19.999;

  print('$age1,$age2,$age3');

  String name = '张三';

  print('$name\n,枸杞');

  bool isMan = true;

  print(isMan?'男':'女');

}
